I have the same prob. im only 20 and i have been smoking since i guess i was 14 years of age. And no, not because of peer pressure or anything, i dont even remeber why i started at the first place. I quit completely when i finished my olevels because of my new friends but then after a year i started again. And i used to smoke over a pack of cigarettes a couple of months back but alhamdulilah i've reduced to about 9-10 per day.
Word of advice, never stop at once! It can have a very negative side effect. My elder brother started smoking when he went abroad about 6-7 years back, when he came back he quit all of a sudden and got seriously ill, physcologically. It has a negative effect on ur brain. Just reduce them by 1 for a couple of weeks and then again reduce 1 and so on.. And try something else which is less harmful, such as chocolates.. They'll help. Always work for me.